Application: Job Scheduling

Support insertion of prioritized jobs in queue.

Support extraction of highest priority job from queue.

Using heaps:

Max(S)

= A[1], $\Theta(1)$

ExtractMax

O(lgn), First 3 lines $\Theta(1)$, fourth line O(lgn)

ExtractMax(S)
1 $\;\;\;\;\;$max = A[1]
2 $\;\;\;\;\;$A[1] = A[HeapSize(A)]
3 $\;\;\;\;\;$HeapSize(A) = HeapSize(A) - 1
4 $\;\;\;\;\;$Heapify(A,1)
5 $\;\;\;\;\;$return max

This corresponds roughly to one iteration of HeapSort.